class LinkedStack<T> 
{
	private static class Node<U> 
	{
		U item;
		Node<U> next;
		Node() { item = null; next = null; }
		Node(U item, Node<U> next)
		{
			this.item = item;
			this.next = next;
		}
		boolean end() { return item == null && next == null; }
	}
	private Node<T> top = new Node<T>();
	public void push(T item)
	{
		top = new Node<T>(item, top);
	}
	public T pop()
	{
		T result = top.item;
		if (!top.end())
			top = top.next;
		return result;
	}
	public static void main(String[] args) 
	{
		LinkedStack<String> lss = new LinkedStack<String>();
		for (String s : "Phaser on stun! ".split(" "))
			lss.push(s);
		String s;
		while ((s = lss.pop()) != null)
		{
			System.out.println(s);
		}
	}
}
